Typewriter ribbon



A ril 14, 1925. 1,533,382

C. CAMPBELL TYPBWRITER RIBBON Filed Dec. 6. 1923 TYPETER RIBBON Z INVENTOR 014K153 CAMPBELL BY M cud M ATTORNEY5' Patented Apr. 14, 1925.

CHARLES cmBELn-or' mew roux, N. Y.

TYPEWRITER RIBBON.

Application filed December 8, 1923. Serial No; 679,038.

- To all whom it may concern:

Be it known that I, CHARLES CAMPBELL, a citizen of the United States, residing at New York city, State of New York, have invented a certain new and useful Improvement in Typewriter Ribbons, of which the following is a clear, full, and exact description.

The present invention relates to typewriter ribbons and more particularly to a novel form of typewriter ribbon composedof matted or felted fibres in place of the woventextile material heretofore employed.

The present method of making typewriter ribbons is extremely costly because of the high cost of the textile material employed, which must necessarily be of a high quality to produce asatisfactory inking surface on the ribbon, and also because of the expensive process of-making the typewriter ribbons therefrom, which involves gumming the edges of the ribbon after it has been cut to the proper width, which is necessary in order to produce a smooth edge which will i not catch or fray in using the ribbon on the typewriter. The ribbons heretofore produced, in addition to being expensive have various defects which have not been commonly understood. If ordinary typewriting, which has been produced with the use of a-typewriter ribbon of the usual fabric material, be examined under a magnifying glass, it will be observed that the various letters are not composed of continuous inked surfaces within the limits of the letters, but

are composed of a series of interrupted inked surfaces having screen or fabric marks corresponding to the outlines of the particular'threads of the typewriter ribbon which were under the corresponding metal types when the impressions were formed on the paper. It has been commonly supposed that the appearance of the letters or impressions on typewritten sheetswas due to the metal type because of its being out of alignment, or 'else to unevenness of the surface of the type, producing a heavier impression on the part of the letter corresponding to portions projecting from the surface of the type. It is apparent, however, from a study of the characters when magnified or of photographic enlargements thereof, that the defect lies mainly in the ribbon itself." The finer the weave of'the textile material used, the less noticeable are the defects in the impressions from the type, but the more costly obviously are the ribbons grades of textile material. typewritten sheet be compared with a printed page, it will be noted by comparison that the typewriting has a blurred or uneven appearance. Heretofore, as far as I amaware, no typewriter ribbon has been rm duced which has been free from the defects above noted.

It is the primary object of the present invention to produce a typewriter ribbon which will produce a full impression similar to printed type, or in other words, which will produce letters having a continuous or solidly inked surface.

Another object of the invention is to produce a typewriter ribbon which may be made without the use of textile or woven material, and which may be made at an extremely low ,cost.

Another'objectof the invention is to provide a typewriter ribbon which may be made in such a manner that the gumming of the edges of the ribbon to prevent their catching in the machine or fraying, may be entirely omitted.

Another object of the invention is to produce a typewriter ribbon which may be made with a thinness of substantially half that of the ordinary typewriter ribbons, therelciiv avoiding the so-called splashing or sprea having the finer If the ordinary ing effect, and thus producing a clearer impression of letters on the paper than has heretofore been attained.

Another object of the invention is to rovide a typewriter ribbon which will be etter adapted than fabric ribbons for use with carbon or carbon papers, whereby clearer impreissions on the carbon copies may be attaine With these and other objects in view, the

invention comprises the various features cates a typewriter in which the ribbon isused in the ordinary manner, being wound upon spools 3 and 4.

In carrying out my invention, I have found thatfibrous cellulose material which does not respond to the test with phloroglucinol hydrochloric acid is the most satisfactory starting material for making my 1mproved typewriter ribbon. This test indicates the presence or absence of lignin impurity, which if present gives a red coloration with a solution of this material. If lignin is present in the fibres, their strength is decreased to such an extent as to render them unsuitable for my ribbons. The fibres which I have found to be most suitable for the purpose are bast fibres of a mulberry, known botanically as the Broussonetia papg m'fem, whose fibres havoc an average length greater than one-half inch. The bast tissue or inner bark layer may be readily separated by the process of steeping or retting, by'which a separation of the fibre from the fleshy or cellular tissue is facilitated. The fibres may be readily purified or bleached, if desired, by employing the usual chemical methods, as will be apparent tothose skilled in the'art.

.The fibres are preferably treated with acids or alkalies to free them from noncellulose constituents and are thereafter filtered or isolated by any preferred mechanical method. By this means, the non-cellulose products may be'hydrolyzed and separated from the cellulose fibres. After the cellulose fibres have been suitably purified and separated from the non-cellulose constituents, a'mat of the fibres is made by depositing a layer thereof upon a screen or. other suitable surface. I preferably suspend the fibres in water and feed the suspension upon a screen so as to form a mat or coating in which the fibres extend in multiple directions so as to interlace, by means of which the tensile strength of the final product will be greatly increased. After a coating of suitable thickness is obtained, the, mat is dried by any suitable means, such as by passing around or between hot rolls, and thereafter the mat is. ironed out in ordento obtain a layer of uniform thickness. I preferably employ a thickness of between .002 to .004 of an inch which will give the desired tensile strength in the ribbon, and which will also, in the finished form, assure a sharp impression of the type on paper. By the use of this ribbon another advantage is obtained in that a much longer length of ribbon may be wound on a spool. I have found that a thickness of ribbon up to .005 of an inch will give satisfactory results,

After the ironing process, the mat is cut into strips of suitable width'for typewriter ribbons, and the strip is inked with inking material in any desired manner, either as is employed in the making of fabric typewriter ribbons or by inking on one side only with a carbonizing ink as is employed for carbon papers. One inking. process which is satisfactory is to pass the strips over a. roller is-finally rolled into a suitable spool, in

which form it is ready to be used.

It is to be understood that I prefer to employ pure collulose material Without the use of loading or fillers, which I have found best adapted for impregnating with ink, and I preferably employ bast fibres, as above described, having an average length of more than one-quarter inch, by means of which the desired tensile strength is attained.

I have found in preparing the ribbon by the above process, that it is unnecessary to gum the edges of the ribbon with glue or gummy material, as is the usual practice in the making of fabric ribbons. By the use of the process above described, the cost of the final ribbon ready for use is less than the cost alone of gumming the edges-of the ordinary typewriter ribbon. It is apparent, therefore, that agreat saving in textile material as well as a saving in labor is accomplished by the use of my process. It is found also that the'results obtained in the use of the ribbon, prepared as above described, are better than that obtained by the the explanation or the reasons why the ribbons, prepared as above described, yield better results, but i believe that by using a rib bon of homogeneous material of substan-' tially half the thickness of that ordinarily employed, there is less distribution or scattering of the force due to the blow of the type than is the case when a fabric ribbon is employed, and the letters or impressions are therefore clearly defined- Also, by the use of a mat of fibers which are laid in multiple directions, or felted, a substantially homogeneous surface is attained which there are a-multiplici-ty of fine interstices, which hold the inking material, and give a substantially continuous ink surface whereby when he ribbon is used in a typewriter, a uniform solidly inked surface within the limits of the letters is attained. Moreover, when textile material is used for typewriter ribbons, a grating or screen eflect appears 7 on the paper, which is readily distinguished by magnification as fabric marks.

The results obtained by the use of my ribbon arenot only better on the first or original sheet than obtained with the ordinary textile ribbon, but the carbon copies are also more distinct. The same explanadirectly to the carbon papers, and without distribution through the greater thickness of material in the ordinary ribbon, which tends to absorb the force of the blow.

the use of the term impregnated with B ink} or its equivalent, as employed in the *claims, I desire to be understood to mean not only saturated or filled with ink, but to comprise also the covering or coating of one side only of the ribbon, which I have found to he -satisfactory in actual practice, and in which the ink does not penetrate all through the ribbon. but adheres to and is impregnated in one side only of the material.

It is to be understood that various changes and modifications may be made in the details of the process, as above set forth, without departing from the spirit and scope of the invention as defined in the claims.

'What I claim as new is p 1. A typewriter ribbon composed mainly of cellulose fibres having a negative test with phloroglucinol hydrochloric acid, and com: prising a narrow felted strip of substantially uniform width and thickness impregnated with ink.

2. In a typewriter ribbon, a strip of uniform width and thickness comprising the elted hast fibres of the Broussomtia papym'fem impregnated with ink.

3. In a typewriter ribbon, a narrow, felted strip of uniform width and thickness comprising mainly fibres of Broussonetz'a papy m'fem laid in multiple directions, characterized by relatively great tensile strength and a substantially homogeneous surface having a great multiplicity of infinitesimal interstices therein, said strip being impregnated with ink, whereby the said interstices serve I to hold the inking material in substantially a continuous plane in juxtaposition to said surface, and whereby when the ribbon is used on a typewriter, a substantially uniform solid inked surface is attained within the limits of the letters corresponding to the type employed, and the screened or dotted appearance of the ordinary typewriter ribbon is thereby avoided.

Signed at New York city this 5th day of December 1923.

CHARLES CAMWBELL. 

